Heat exchanger with interspersed arrangement of cross-flow structures

ABSTRACT

A heat exchanger includes a separator member that divides a first flow passage from a second flow passage. The heat exchanger also includes a plurality of first hollow members that extend across the first flow passage at respective non-orthogonal angles. The plurality of first hollow members are fluidly connected to the second flow passage. Moreover, the heat exchanger includes a plurality of second hollow members that extend across the second flow passage at respective non-orthogonal angles. The plurality of second hollow members are fluidly connected to the first flow passage.

TECHNICAL FIELD

The present disclosure generally relates to a heat exchanger and, moreparticularly, relates to a heat exchanger with an interspersedarrangement of cross-flow structures.

BACKGROUND

Heat exchangers have been developed for various devices, such as enginesystems, computer systems, HVAC systems, and more. The heat exchangersare configured for directing heat within the device to components wheresuch heat is beneficial to its operating performance, for directing heataway from components that normally cannot tolerate high temperatures,and/or where system operational constraints require controlledtemperatures.

For example, gas turbine engines may include various heat exchangers. Inone example, a class of heat exchangers known as recuperators have beendeveloped to recover heat from the engine exhaust, which is otherwisewasted energy, and redirect the recovered engine exhaust heat to thepre-combustion portion of the engine, to increase its overall engineefficiency. Specifically, the recuperator is a heat exchanger thattransfers some of the waste heat in the exhaust to the compressed airbefore it enters the combustion portion of the engine, therebypreheating it before entering the fuel combustor stage. Since thecompressed air has been pre-heated, less fuel is needed to heat thecompressed air/fuel mixture up to the desired turbine inlet temperature.By recovering some of the energy usually lost as waste heat, therecuperator can make a gas turbine engine significantly more efficient.

In another example, cooling air may be provided to various turbineengine components using cooling air extracted from other parts of theengine. More specifically, in some gas turbine engines, cooling air isextracted from the discharge of the compressor, and is then directed tocertain portions of the turbine. During some operating conditions, theair that is extracted from the engine for cooling may be at temperaturesthat require the air to be cooled before being directed to theparticular component requiring cooling. To achieve the required cooling,cooling air may be directed through one or more heat exchangers withinthe engine.

Conventional heat exchangers may be too heavy, bulky, and/or may notprovide acceptable performance characteristics. Other heat exchangersmay be too expensive and/or difficult to manufacture. Moreover, someheat exchangers may be susceptible to thermo- mechanical fatigue, whichreduces their service life and/or necessitates costly repairs orreplacement.

Hence, there is a need for improved heat exchangers for use in gasturbine engines and other applications having improved efficiency,reduced manufacturing costs, and increased operating lifespan. Thepresent disclosure addresses at least these needs.

BRIEF SUMMARY

In one embodiment, a heat exchanger is disclosed that includes aseparator member that divides a first flow passage of the heat exchangerfrom a second flow passage of the heat exchanger. The heat exchangeralso includes a plurality of first hollow members that extend across thefirst flow passage and that are attached to the separator member atrespective non-orthogonal angles. The plurality of first hollow membersbeing fluidly connected to the second flow passage. Moreover, the heatexchanger includes a plurality of second hollow members that extendacross the second flow passage and that are attached to the separatormember at respective non-orthogonal angles. The plurality of secondhollow members are fluidly connected to the first flow passage. Thefirst flow passage is configured to receive a first fluid that flowsthrough the first flow passage and into the plurality of second hollowmembers. The second flow passage is configured to receive a second fluidthat flows through the second flow passage and into the plurality offirst hollow members. The first fluid is configured to exchange heatwith the second fluid as the first fluid flows through the first flowpassage and over the plurality of first hollow members. The second fluidis configured to exchange heat with the first fluid as the second fluidflows through the second flow passage and over the plurality of secondhollow members.

In another embodiment, a heat exchanger is disclosed that includes afirst separator member and a second separator member. The firstseparator member divides an intermediate flow passage of the heatexchanger from an upper flow passage of the heat exchanger. The secondseparator member divides the intermediate flow passage from a lower flowpassage of the heat exchanger. The upper flow passage has a first inletand a first outlet and is configured to direct flow of a first fluidalong a first flow axis from the first inlet to the first outlet. Theintermediate flow passage has a second inlet and a second outlet and isconfigured to direct flow of a second fluid along a second flow axisfrom the second inlet to the second outlet. The heat exchanger furtherincludes a hollow member that extends across the intermediate flowpassage and that is attached to the first separator member and thesecond separator member. The hollow member is fluidly connected to theupper flow passage and the lower flow passage. The hollow member isoriented with respect to the first flow axis to direct flow of the firstfluid through the at least one hollow member along the first flow axis.

Moreover, a method of manufacturing a heat exchanger is disclosed thatincludes forming a first flow structure with a first flow passage and asecond flow structure with a second flow passage. This includes forminga separator member that divides the first flow passage from the secondflow passage. The method also includes forming a plurality of firsthollow members that extend across the first flow passage and that areattached to the separator member at respective non-orthogonal angles.The plurality of first hollow members are fluidly connected to thesecond flow passage. The method additionally includes forming aplurality of second hollow members that extend across the second flowpassage and that are attached to the separator member at respectivenon-orthogonal angles. The plurality of second hollow members arefluidly connected to the first flow passage. The first flow passage isconfigured to receive a first fluid that flows through the first flowpassage and into the plurality of second hollow members. The second flowpassage is configured to receive a second fluid that flows through thesecond flow passage and into the plurality of first hollow members. Thefirst fluid is configured to exchange heat with the second fluid as thefirst fluid flows through the first flow passage and over the pluralityof first hollow members. The second fluid is configured to exchange heatwith the first fluid as the second fluid flows through the second flowpassage and over the plurality of second hollow members.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will hereinafter be described in conjunction withthe following drawing figures, wherein like numerals denote likeelements, and wherein:

FIG. 1 is a schematic side view of a gas turbine engine with a heatexchanger according to exemplary embodiments of the present disclosure;

FIG. 2 is a perspective view of a heat exchanger according to exampleembodiments of the present disclosure, wherein the heat exchanger may beconfigured for use within the gas turbine engine of FIG. 1;

FIG. 3 is a section view of the heat exchanger taken along the line 3-3of FIG. 2;

FIG. 4 is a section view of the heat exchanger taken along the line 4-4of FIG. 2;

FIG. 5 is a section view of the heat exchanger taken along the line 5-5of FIG. 2;

FIG. 6 is a section view of the heat exchanger according to additionalembodiments of the present disclosure;

FIG. 7 is a section view of the heat exchanger according to additionalembodiments of the present disclosure; and

FIG. 8 is a section view of a hollow member of the heat exchanger takenalong the line 8-8 of FIG. 7.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and isnot intended to limit the present disclosure or the application and usesof the present disclosure. As used herein, the word “exemplary” means“serving as an example, instance, or illustration.” Thus, any embodimentdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other embodiments. Furthermore, as usedherein, numerical ordinals such as “first,” “second,” “third,” etc.simply denote different singles of a plurality unless specificallydefined by language in the appended claims. All of the embodiments andimplementations of the heat exchange systems described herein areexemplary embodiments provided to enable persons skilled in the art tomake or use the invention and not to limit the scope of the presentdisclosure, which is defined by the claims. Furthermore, there is nointention to be bound by any expressed or implied theory presented inthe preceding technical field, background, brief summary, or thefollowing detailed description.

The present disclosure relates to a heat exchanger, which may besuitable for use in gas turbine engines and other applications. The heatexchanger may provide improved heat transfer performance, increasedmanufacturability, and/or improved operational lifespan. In oneimplementation, the heat exchanger is embodied as a recuperator or othersimilar component for heating a fluid (e.g., air) prior entry intoanother component (e.g., a combustor). In another implementation, theheat exchanger is embodied as a cooling air heat exchanger for reducingthe temperature of cooling fluid (e.g., air) prior to its delivery toanother component that requires cooling (e.g., a turbine component orcooling system). However, it will be appreciated that the presentlydisclosed heat exchanger is not limited to use in the aforementionedembodiments. Rather, it is expected that the heat exchanger disclosedherein will be suitable for use in a wide array of applications. Somenon-limiting examples include engine oil and/or fuel cooling, auxiliarypower units, environmental control systems, chemical reaction systems,and any other systems where heat transfer/exchange between two fluidmedia is either required or desirable.

In general, the heat exchanger may include a plurality of structuresthat define first flow passages and second flow passage that aredisposed in an alternating arrangement. The heat exchanger may alsoinclude a plurality of first hollow members (e.g., tubes, conduits,etc.) that extend across a respective first flow passage and that arefluidly connected to opposing second flow passages. Moreover, the heatexchanger may include a plurality of second hollow members (e.g., tubes,conduits, etc.) that extend across a respective second flow passage andthat are fluidly connected to opposing first flow passages. Accordingly,a first fluid may flow along a first flow axis through one of the firstflow passages, and the first fluid may flow via the second hollowmembers to another first flow passage. Likewise, a second fluid may flowalong a second flow axis through one of the second flow passages, andthe second fluid may flow via the first hollow members to another secondflow passage. The first fluid and the second fluid may exchange heatduring such flow.

At least one of the first hollow members may extend along an axis thatis disposed at a non-orthogonal angle relative to the second flow axisof the second flow passage. Accordingly, a pressure differential mayexist along the first hollow member to draw the second fluidtherethrough. Likewise, at least one of the second hollow members mayextend along an axis that is disposed at a non-orthogonal angle relativeto the first flow axis. Accordingly, a pressure differential may existalong the second hollow member to draw the first fluid therethrough. Assuch, the heat exchanger may be highly efficient, lightweight, and mayhave a relatively long operating life.

Referring now particularly to FIG. 1, a simplified cross section view ofan exemplary gas turbine engine 100 is depicted. The depicted engine 100includes an intake section 102, a compressor section 104, a combustionsection 106, a turbine section 108, and an exhaust section 112. Theintake section 102, compressor section 104, combustion section 106,turbine section 108, and exhaust section 112 are all mounted within anacelle 114. The compressor section 104, combustion section 106, andturbine section 108 are all mounted within an engine case 116.

The intake section 102 includes a fan 118, which draws air into theengine 100 and accelerates it. A fraction of the accelerated fan airthat is exhausted from the fan 118 is directed through a fan air bypassduct 122, which is defined by an outer fan duct 124, and which is spacedapart from and surrounds an inner fan duct 126. Most of the fan air thatflows through the fan air bypass duct 122 is discharged from the bypassduct 122 to generate a forward thrust. The fraction of fan air that doesnot flow into the fan air bypass duct 122 is directed into thecompressor section 104.

The compressor section 104 can include one or more compressors. Theengine 100 depicted in FIG. 1 includes two compressors: an intermediatepressure compressor 132 and a high pressure compressor 134. No matterthe number of compressors it includes, the air that is directed into thecompressor section 104 is pressurized to a relatively high pressure. Therelatively high pressure air that is discharged from the compressorsection 104 is directed into the combustion section 106.

The combustion section 106 includes a combustor 136 that is coupled toreceive both the relatively high pressure air and atomized fuel. Therelatively high pressure air and atomized fuel are mixed within thecombustor 136 and the mixture is ignited to generate combusted air. Thecombusted air is then directed into the turbine section 108.

The depicted turbine section 108 includes three turbines: a highpressure turbine 138, an intermediate pressure turbine 142, and a lowpressure turbine 144, though it should be appreciated that any number ofturbines may be included. The combusted air directed into the turbinesection 108 expands through each of turbines 138, 142, 144, causing eachto rotate. The air is then exhausted through a propulsion nozzle 146disposed in the exhaust section 112 to provide additional forwardthrust. As the turbines 138, 142, 144 rotate, each drives equipment inthe gas turbine engine 100 via concentrically disposed shafts or spoolsas best seen in FIG. 1.

The engine 100 may further include at least one heat exchanger 200(shown schematically). In some embodiments, the heat exchanger 200 maybe included in a cooling air system 190 for providing cooling air tocool various portions and/or components within the engine 100. Forexample, the heat exchanger 200 of the cooling air system 190 mayextract cooling air from the discharge of the compressor section 104 anddirect the cooling air to the turbine section 108. Additionally, or inthe alternative, the heat exchanger 200 may be included in a recuperator192 for providing heated air to various portions and/or componentswithin the engine 100. For example, the recuperator 192 may recover hotengine exhaust gas from the combustor 136 and the heat exchanger 200therein may transfer heat from the exhaust gas to the air flowing intothe combustor 136.

With reference to FIG. 2, the heat exchanger 200 will be discussed ingreater detail according to example embodiments. For clarity and ease ofillustration, portions of the heat exchanger 200 are hidden from view.Specifically, an upper portion is sectioned away at an angle to revealinterior features. Also, for reference purposes, a Cartesian coordinatesystem is included with a first axis 201, a second axis 202, and a thirdaxis 203.

Generally, the heat exchanger 200 may include a plurality of first flowstructures 204 and a plurality of second flow structures 254. As shownin the illustrated embodiment, the first flow structures 204 and thesecond flow structures 254 may be generally box-shaped and hollow insome embodiments. The second flow structures 254 may be larger than thefirst flow structures 204 in some embodiments. In other embodiments, thesecond flow structures 254 may be smaller than the first flow structures204. It will be appreciated, however, that the shape, arrangement,geometry, etc. of the first and second flow structures 204, 254 may varyfrom the illustrated embodiments without departing from the scope of thepresent disclosure. The relative sizes of the first and second flowstructures 204, 254 may be configured according to the operationalrequirements of the heat exchanger 200. In some embodiments, forexample, the first and second flow structures 204, 254 may be shaped,arranged, and configured as a conformal heat exchanger, in that the heatexchangers 200 conforms to the curvature of adjacent components of theengine 100 (e.g., to form an annular ring). Other shapes and sizes arepossible to conform to available installation space in otherimplementations as well.

The first flow structures 204 may be substantially similar to eachother. The first flow structures 204 may define respective first flowpassages 206 that receive flow of a first fluid (e.g., a first gas). Thefirst flow passages 206 may each include an inlet 208 and an outlet 210,and a first flow axis 212 may extend between the inlet 208 and theoutlet 210. In some embodiments, the first flow axis 212 may begenerally straight and parallel to the first axis 201.

Also, the second flow structures 254 may be substantially similar toeach other. The second flows structures 254 may define respective secondflow passages 256 that receive flow of a second fluid (e.g., a secondgas). The second flow passages 256 may each include an inlet 260 and anoutlet 258, and a second flow axis 262 may extend between the inlet 260and the outlet 258. In some embodiments, the second flow axis 262 may begenerally straight and parallel to the second axis 202. The second flowaxis 262 may be substantially orthogonal in a cross flow arrangement tothe first flow axis 212 in some embodiments. In additional embodiments,the heat exchanger 200 may have a counterflow arrangement. Also, theheat exchanger 200 may be conformal in nature where the flow structures204, 254 are curved to allow for installation in an annular or otherwisecurved envelope.

The first and second flow structures 204, 254 may be stacked in analternating pattern atop each other along the third axis 203. Also, thefirst flow structures 204 and the second flow structures 254 may be inan alternating arrangement with first flow structures 204 disposedbetween neighboring pairs of the second flow structures 254 and viceversa. This pattern may be continued until there is a suitable number offirst and second flow structures 204, 254. In the illustratedembodiment, for example, the heat exchanger 200 includes a lower firstflow structure 205 and an upper first flow structure 207. Also, in theillustrated embodiment, the heat exchanger 200 includes a lower secondflow structure 255, an upper second flow structure 257, and anintermediate second flow structure 259. (In FIG. 2, portions of theupper first flow structure 207 and the upper second flow structure 257are hidden for clarity.) The intermediate second flow structure 259 maybe disposed between the opposing lower first flow structure 205 andupper first flow structure 207. The lower first flow structure 205 maybe disposed between the opposing lower second flow structure 255 andintermediate second flow structure 259. The upper second flow structure207 may be disposed between the opposing intermediate second flowstructure 259 and upper second flow structure 257. It will beappreciated that there may be additional flow structures within the heatexchanger 200 without departing from the scope of the presentdisclosure.

In some embodiments, the heat exchanger 200 may include a plurality ofseparator members 220. The separator members 220 may be relatively flat,unitary panels. Accordingly, the separator members 220 may besubstantially parallel to a plane defined by the first axis 201 and thesecond axis 202. Each separator member 220 may divide one of the firstflow passages 206 from an adjacent second flow passage 256. Thus, insome embodiments, the separator member 220 may partly define one of thefirst flow structures 204 and may partly define an adjacent one of thesecond flow structures 254.

The first flow structures 204 may also include a respective first sidewall 222 and a respective second side wall 224. The first and secondside walls 222, 224 may be flat walls that are substantially parallel toa plane defined by the first and third axes 201, 203. The first andsecond side walls 222, 224 may be spaced apart along the second axis 202to define a flow width. Accordingly, the first and second side walls222, 224 and a pair of the separator members 220 may cooperate to definethe inlet 208 of one of the first flow passages 206. Likewise, the firstand second side walls 222, 224 and the pair of separator members 220 maycooperate to define the outlet 210 of one of the first flow passages206.

The second flow structures 254 may also include a respective third sidewall 226 and a respective fourth side wall 228. The third and fourthside walls 226, 228 may be flat walls that are substantially parallel toa plane defined by the second and third axes 202, 203. The third andfourth side walls 226, 228 may be spaced apart along the first axis 201.Accordingly, the third and fourth side walls 226, 228 and a pair of theseparator members 220 may cooperate to define the inlet 260 of one ofthe second flow passages 256. Likewise, the third and fourth side walls226, 228 and the pair of separator members 220 may cooperate to definethe outlet 258 of one of the second flow passages 256.

Referring now to FIGS. 2, 3, and 4, the interior of the first flowstructures 204 and the second flow structures 254 will be discussed. Asshown, the heat exchanger 200 may include a plurality of support posts209. The support posts 209 may be elongate and may extend substantiallyparallel to the third axis 203. Also, the support posts 209 may have arounded (e.g., circular) cross section. Moreover, the support posts 209may have a solid core (as opposed to being hollow). The support posts209 may be fixed at one end to a separator member 220 and fixed at theopposite end to an opposing separator member 220. In some embodiments,the support posts 209 may be disposed within and may extend across thefirst flow passages 206, substantially parallel to the third axis 203.The support posts 209 may provide load bearing support to the heatexchanger 200. The arrangement of the support posts 209 may be tailoredfor providing needed support. For example, as shown in the embodiment ofFIG. 2, groups of the support posts 209 may be substantially aligned andarranged in rows (extending along the second axis 202). There may bemultiple rows of the support posts 209, and the rows may be spaced apartalong the first axis 201. Accordingly, the support posts 209 may providehigh strength and robustness to the heat exchanger 200. In someembodiments, the support posts 209 may also provide a heat transfer pathbetween fluids in the first and second flow passages 206, 256.

It will be appreciated that the support posts 209 may be configureddifferently than the embodiments illustrated. For example, the heatexchanger 200 may include support posts 209 that are disposed within thesecond flow passage 256. Also, the support posts 209 may, in someembodiments, include fins or other projections that increase the heattransfer properties of the support post 209.

Moreover, the heat exchanger 200 may include a plurality of first hollowmembers 230. The first hollow members 230 may be configured as tubes,cylinders, pipes, or other fluid conduits. Accordingly, as shown in FIG.3, the first hollow members 230 may include an outer shell 232 and aninterior 234 that is hollow. In some embodiments, the first hollowmembers 230 may have a rounded (e.g., circular) cross section on itsouter diameter surface as well as its inner diameter surface. In someembodiments, the first hollow members 230 may have a diameter betweenapproximately 0.040 to 0.200 inches. Also, in some embodiments, thefirst hollow members 230 may have a length between approximately 0.050to 0.300 inches.

Each first hollow member 230 may include a first end 236 and a secondend 238 (FIG. 3). The first hollow members 230 may also include arespective first cross-flow axis 240, which extends between the firstend 236 and the second end 238. In some embodiments, the firstcross-flow axis 240 is substantially straight.

The first end 236 may be fixedly attached to one of the separatormembers 220, and the second end 238 may be fixedly attached to anopposing one of the separator members 220. The first cross-flow axis 240of the first hollow member 230 may be oriented at a non-orthogonal angle242 with respect to the attached separator member 220. In someembodiments, different hollow members 230 may be disposed at differentangles 242 with respect to a common separator member 220.

In some embodiments, the first hollow members 230 may be disposed withinand may extend across the first flow passages 206. Also, as shown inFIG. 3, the first end 236 may be fluidly connected to one of the secondflow passages 256, and the second end 238 may be fluidly connected to aneighboring second flow passage 256. As shown in FIG. 5, there may be aplurality of first holes 244 through the separator members 220. Thefirst holes 244 may fluidly connect the interior 234 of a respectivefirst hollow member 230 to the second flow passage 256. Accordingly,fluid within one second flow passage 256 may flow through the firsthollow members 230 to the neighboring second flow passage 256. Thisfluid flow is indicated by arrows 261 in FIG. 3, wherein a second fluidflows from the second flow passage 256 of the intermediate second flowstructure 259, through one of the first hollow members 230, to thesecond flow passage 256 of the lower second flow structure 255. Thesecond fluid is also shown flowing back to the second flow passage 256of the intermediate second flow structure 259 through another firsthollow member 230. Meanwhile, the first fluid may be flowing through thefirst flow passage 206 and flowing around the first flow hollow members230. The first and second fluids may have different temperatures, andthe first hollow members 230 may be formed with materials having highheat transfer properties. Accordingly, the second fluid may exchangeheat with the first fluid as the second fluid passes through the firsthollow member 230 that is in direct contact with the first fluid.

The arrangement of the first hollow members 230 may be configured toprovide desirable heat transfer properties, to reduce pressure dropacross the heat exchanger 200, etc. As stated, the first hollow members230 may be disposed at an angle 242 with respect to the separator member220 and with respect to the second flow axis 262. In some embodiments,the first hollow members 230 are inclined within the plane defined bythe second axis 202 and the third axis 203. As such, the first hollowmembers 230 may be inclined generally with respect to the fluid flowpath (i.e., with respect to the second flow axis 262). Also, the firstend 236 and the second end 238 may be spaced apart with respect to thesecond axis 202. In other words, the first end 236 of the first hollowmember 230 may be closer to the inlet 260 of the second flow passage256, and the second end 240 may be closer to the outlet 258 of thesecond flow passage 256, or vice versa.

Accordingly, this inclined orientation may provide a pressuredifferential between the first end 236 and the second end 238 of thefirst hollow member 230. The pressure differential may force secondfluid through the first hollow members 230. This can enhance the heattransfer performance of the heat exchanger 200. Also, scoop-likefeatures may be implemented at the inlet ends (e.g., the first ends 236)to increase the flow rate.

Furthermore, as shown in the embodiment of FIGS. 2, 3, and 5, groups ofthe first hollow members 230 may be substantially aligned and arrangedin rows (extending along the second axis 202). There may be multiplerows of the first hollow members 230, and the rows may be spaced apartalong the first axis 201. In some embodiments, there may be a first row246 and a second row 248 of first hollow members 230. The first row 246may be offset from the second row 248 at a distance 253 measured alongthe second axis 202. The angle 242 of the hollow members 230 within thefirst row 246 may be different from the angle 242 of the hollow members230 within the second row 248. In some embodiments, the angle 242 of thehollow members 230 of the first row 246 may be substantially equal andopposite the angle 242 of the hollow members 230 of the second row 248as shown in FIG. 3. For example, the angle 242 of the hollow members 230of the first row 246 may be forty-five degrees (45°) in someembodiments, the angle 242 of the hollow members 230 of the second row248 may be negative forty-five degrees (−45°).

In addition, the heat exchanger 200 may include a plurality of secondhollow members 280. The second hollow members 280 may be configured astubes, cylinders, pipes, or other fluid conduit. Accordingly, as shownin FIG. 4, the second hollow members 280 may include an outer shell 282and an interior 284 that is hollow. In some embodiments, the secondhollow members 280 may have a rounded (e.g., circular) cross section onits outer diameter surface as well as its inner diameter surface. Insome embodiments, the second hollow members 280 may have a diameterbetween approximately 0.040 to 0.200 inches. Also, in some embodiments,the second hollow members 280 may have a length between approximately0.050 to 0.300 inches.

Each second hollow member 280 may include a first end 286 and a secondend 288 (FIG. 4). The second hollow members 280 may also include arespective second cross-flow axis 290, which extends between the firstend 286 and the second end 288. In some embodiments, the firstcross-flow axis 290 is substantially straight.

The first end 286 may be fixedly attached to one of the separatormembers 220, and the second end 288 may be fixedly attached to anopposing one of the separator members 220. The second cross-flow axis290 of the second hollow members 280 may be oriented at non-orthogonalangles 292 with respect to the attached separator member 220. In someembodiments, different hollow members 280 may be disposed at differentangles 292 with respect to a common separator member 220.

In some embodiments, the second hollow members 280 may be disposedwithin and may extend across the second flow passages 256. Also, asshown in FIG. 4, the first end 286 may be fluidly connected to one ofthe first flow passages 206, and the second end 288 may be fluidlyconnected to a neighboring first flow passage 206. FIG. 5 shows openingsin the separator member 220, and as shown, there may be a plurality ofsecond holes 294 that fluidly connect the interior 284 of the secondhollow members 280 to the first flow passage 206. Accordingly, fluidwithin one first flow passage 206 may flow through the second hollowmembers 280 to the neighboring first flow passage 206. This fluid flowis indicated by arrows 263 in FIG. 4, wherein a first fluid flows fromthe first flow passage 206 of the lower first flow structure 205,through one of the second hollow members 280, to the first flow passage206 of the upper first flow structure 207. The first fluid is also shownflowing back to the first flow passage 206 of the lower first flowstructure 205 through another second hollow member 280. Meanwhile, thesecond fluid may be flowing through the second flow passage 256 andflowing around the second hollow members 280. The first and secondfluids may have different temperatures, and the second hollow members280 may be formed with materials having high heat transfer properties.Accordingly, the first fluid may exchange heat with the second fluid asthe first fluid passes through the second hollow member 280.

The arrangement of the second hollow members 280 may be configured toprovide desirable heat transfer properties, to reduce pressure dropacross the heat exchanger 200, etc. As stated, the second hollow members280 may be disposed at an angle 292 with respect to the separator member220 and with respect to the first flow axis 212. In some embodiments,the second hollow members 280 are inclined within the plane defined bythe first axis 201 and the third axis 203. As such, the second hollowmembers 280 may be inclined generally with respect to the fluid flowpath (i.e., with respect to the first flow axis 212). Also, the firstend 286 and the second end 288 may be spaced apart with respect to thefirst axis 201. In other words, the first end 286 of the second hollowmember 280 may be closer to the inlet 208 of the first flow passage 206,and the second end 288 may be closer to the outlet 210 of the first flowpassage 206, or vice versa.

Accordingly, this inclined orientation may provide a pressuredifferential within the fluid flow between the first end 286 and thesecond end 288. The pressure differential may force the fluid throughthe second hollow members 280. This flow through the member enhances theheat transfer performance of the heat exchanger 200. Also, scoop-likefeatures may be implemented at the inlet ends (e.g., the first ends 286)to increase the flow rate.

Furthermore, as shown in the embodiment of FIGS. 2 and 3, groups of thesecond hollow members 280 may be substantially aligned and arranged inrows (extending along the first axis 201). There may be multiple rows ofthe second hollow members 280, and the rows may be spaced apart alongthe second axis 202. In some embodiments represented in FIG. 5, theremay be a first row 296 and a second row 298 of first hollow members 230.The first row 296 may be offset from the second row 298 at a distance251 measured along the first axis 201. The angle 292 (FIG. 4) of thehollow members 230 within the first row 296 may be different from theangle 292 of the hollow members 280 within the second row 298. In someembodiments, the angle 292 of the hollow members 280 of the first row296 may be substantially equal and opposite the angle 292 of the hollowmembers 280 of the second row 298 as shown in FIG. 4. For example, theangle 292 of the hollow members 280 of the first row 296 may beforty-five degrees (45°) in some embodiments, and the angle 292 of thehollow members 280 of the second row 298 may be negative forty-fivedegrees (−45°).

The interior 234 of the first hollow members 230 may have a smallercross sectional area (e.g., smaller inner diameter) than that of theinterior 284 of the second hollow members 280. Furthermore, the lengthof the first hollow members 230 (measured from the first end 236 to thesecond end 238 along the axis 240) may be shorter than that of thesecond hollow member 280. The dimensions of the second hollow members280 may provide a large amount of exposure within the flow of fluidwithin the second passages 256 to promote heat transfer between thesecond fluid within the second passages 256 and the first fluid withinthe second hollow members 280. These lengths, diameters and angles maybe configured according to the performance and other requirements of theheat exchanger 200.

In some embodiments, the first flow passages 206 as well as the secondhollow members 280 may receive a hot first fluid, and the second flowpassages 256 as well as the first hollow members 230 may receive a coolsecond fluid. Accordingly, heat may transfer from the first fluid to thesecond fluid via flow through the heat exchanger 200.

The heat exchanger 200 may be configured to direct flow of the firstfluid generally along the flow axis 212 as well as in a cross-flowdirection along the axis 290 across the second flow passage 256.Likewise, the heat exchanger 200 may be configured to direct flow of thesecond fluid generally along the flow axis 262 as well as in across-flow direction along the axis 240 across the first flow passage206. The first hollow members 230 may be inclined or otherwise orientedto direct flow of the second fluid along the axis 262 of the secondpassageway 256. Likewise, the second hollow members 280 may be inclinedor otherwise oriented to direct flow of the first fluid along the axis212 of the first passageway 206. Accordingly, the fluids may flow in avariety of directions through the heat exchanger 200 to increaseefficiency.

Also, the plurality of first hollow members 230 may be inclined within aplane (e.g., the plane defined by the second and third axes 202, 203),and the plurality of second hollow members 280 may be inclined within aplane (e.g., the plane defined by the first and third axes 201, 203. Theplane of the first hollow members 230 may be approximately orthogonal tothe plane of the second hollow members 280. Other orientations arewithin the scope of the present disclosure as well.

As shown in FIG. 4, a portion of the first fluid may flow around thecriss-crossing, lattice-like arrangement of the first hollow members 230as the first fluid flows through the first passageway 206. Also, aportion of the first fluid may flow through second hollow members 280 toan adjacent first passageway 206. Thus, the first fluid has an “externalflow” about the first hollow members 230 for heat exchange with thesecond fluid, and the first fluid has an “internal flow” through thesecond hollow members 280 for heat exchange with the second fluid.Likewise, as shown in FIG. 3, a portion of the second fluid flows aroundthe criss-crossing, lattice-like arrangement of the second hollowmembers 280 as the second fluid flows through the second passageway 256.Also, a portion of the second fluid may flow through first hollowmembers 230 to an adjacent second passageway 256. Accordingly, thesecond fluid has an “external flow” about the second hollow members 280for heat exchange with the first fluid, and the second fluid has an“internal flow” through the first hollow members 230 for heat exchangewith the first fluid.

As shown, the lattice-like arrangement of the first hollow members 230may be oriented substantially perpendicular to the flow directionthrough the first passageway 206, and the lattice-like arrangement ofthe second hollow members 280 may be oriented substantiallyperpendicular to the flow direction through the second passageway 256.Also, in the illustrated embodiment, the flows are in a cross flowmanner with respect to each other; therefore, the lattice-likearrangements may be substantially perpendicular with respect to eachother. Accordingly, this provides a high degree of exposure for highlyefficient heat transfer between the two fluids.

Flow apportionment throughout the heat exchanger may be accomplished bycomputational fluid dynamics (CFD) analysis and optimization, forexample, utilizing conjugate heat transfer analysis, where the fluidmechanics and structural temperatures are solved in a single coupledanalysis. Commercial software codes such as CD-adapco STAR-CCM+ fromSiemens AG of Munich, Germany or ANSYS CFX are examples of such codesthat may be used by those skilled in the art. To accomplish the optimalflow apportionment and resulting heat transfer, the dimensions andquantities of the first hollow members 230 and the geometric spacingbetween adjacent second hollow members 280 may be configured to providesuitable flow inside the first hollow members 230 and suitable flowaround the second hollow members 280. Similarly, to accomplish theoptimal flow apportionment and resulting heat transfer, the dimensionsand quantities of the second hollow members 280 and the geometricspacing between adjacent first hollow members 230 may be configured toprovide suitable flow inside the second hollow members 280 and suitableflow around the first hollow members 230. Various types of flow scoopsmay be employed on the first end 236 inlet of one or more first hollowmembers 230 to facilitate obtaining a predetermined flow 261 through thefirst hollow members 230. Likewise, various types of flow scoops may beemployed on the first end 286 inlet of one or more second hollow members280 to facilitate obtaining a predetermined flow 263 through the secondhollow members 280.

Referring now to FIG. 6, additional embodiments of the heat exchanger300 are illustrated according to the present disclosure. Only a portionis shown for clarity. The heat exchanger 300 may be substantiallysimilar to the embodiment of FIGS. 2-5 except as noted. Components thatcorrespond to those of FIGS. 2-5 are indicated with correspondingreference numbers increased by 100.

As shown, the first hollow members 330 may have a contoured axis 340. Inother words, the first hollow members 330 may curve as they extendacross the first flow passage 306. Like the embodiment of FIGS. 2-5 thefirst hollow members 330 are attached to the separator members 320 atnon-orthogonal angles. Also, the first hollow members 330 may beoriented with respect to the flow axes 362 such that the first hollowmembers 330 direct flow of the second fluid somewhat along the axis 362of the second passageways 356. Moreover, as shown in FIG. 6, thecross-sectional area of at least one hollow member 330 may vary alongits length, for example, to increase the flow through the hollow member330. It will be appreciated that second hollow members of the heatexchanger 300 may be similar to the first hollow members 330 and maycurve and attach to the separator members 320 at non-orthogonal anglesas well.

Referring now to FIGS. 7 and 8, additional embodiments of the heatexchanger 400 are illustrated according to the present disclosure. Onlya portion is shown for clarity. The heat exchanger 400 may besubstantially similar to the embodiment of FIGS. 2-5 except as noted.Components that correspond to those of FIGS. 2-5 are indicated withcorresponding reference numbers increased by 200.

As shown, the first hollow members 430 may include at least oneprojection 483 that projects outward from the outer shell 432 into thefirst flow passage 406. The projection 483 may be a thin, annulardisc-like fin that encircles the outer shell 432 in some embodiments.There may be several projections 483 on the first hollow member 430. Theprojections 483 may promote heat transfer for higher efficiencyoperation of the heat exchanger 400. Other projections 483 fall withinthe scope of the present disclosure, such as pins, helical projections,etc. Furthermore, the second hollow members and/or other portions of theheat exchanger 400 may include projections as well.

Furthermore, the heat exchanger 400 may include one or more scoopstructures 499. The scoop structure 499 may project from the separatormember 420, proximate the first end 436 (i.e., the inlet end) of thefirst hollow member 430. The scoop structure 499 may also curve in anupstream direction within the second passageway 456. The scoop structure499 may direct flow of the second fluid into the first hollow member430.

The heat exchangers of the present disclosure may be manufactured in avariety of ways without departing from the scope of the presentdisclosure. It will be appreciated that certain features of thepresently described heat exchange systems may be prohibitively expensiveto manufacture using conventional manufacturing techniques. Thesefeatures include the inclined or contoured surfaces, the interspersedcross-flow hollow members, the varying wall thickness features, amongothers. As such, designs in accordance with the present disclosure arenot known in the prior art.

However, in some embodiments, the heat exchanger of the presentdisclosure may be formed using additive manufacturing techniques (e.g.,3D printing techniques). Thus, the heat exchanger may be formed moreaccurately and at a significantly reduced cost as compared totraditional manufacturing techniques. The heat exchanger may be asubstantially unitary, one-piece component using these techniques. Inother words, the flow structures, the hollow members, projections, andother features of the heat exchanger may be integrally connected so asto be a unitary, one-piece heat exchanger.

Additive manufacturing techniques include, for example, direct metallaser sintering (DMLS—a form of direct metal laser fusion (DMLF)) orelectron beam additive manufacturing. The heat exchanger may bemanufactured from aluminum, titanium, steel, and nickel-based alloys.Still further, casting or metal injection molding (MIM) may be employed.In some embodiments, the heat exchanger of the present disclosure may beconstructed using techniques disclosed in US Patent No. 2013/0236299,the disclosure of which is hereby incorporated by reference in itsentirety.

Accordingly, the heat exchanger of the present disclosure provideshighly efficient heat exchange. Also, the heat exchanger may belightweight, and yet, robust and strong for a long operating life.Additionally, the heat exchanger may provide manufacturing benefits aswell.

While at least one exemplary embodiment has been presented in theforegoing detailed description, it should be appreciated that a vastnumber of variations exist. It should also be appreciated that theexemplary embodiment or exemplary embodiments are only examples, and arenot intended to limit the scope, applicability, or configuration of thepresent disclosure in any way. Rather, the foregoing detaileddescription will provide those skilled in the art with a convenient roadmap for implementing an exemplary embodiment of the present disclosure.It is understood that various changes may be made in the function andarrangement of elements described in an exemplary embodiment withoutdeparting from the scope of the present disclosure as set forth in theappended claims.

What is claimed is:
 1. A heat exchanger comprising: a separator memberthat divides a first flow passage of the heat exchanger from a secondflow passage of the heat exchanger; a plurality of first hollow membersthat extend across the first flow passage and that are attached to theseparator member at respective non-orthogonal angles, the plurality offirst hollow members being fluidly connected to the second flow passage;and a plurality of second hollow members that extend across the secondflow passage and that are attached to the separator member at respectivenon-orthogonal angles, the plurality of second hollow members beingfluidly connected to the first flow passage; wherein the first flowpassage is configured to receive a first fluid that flows through thefirst flow passage and into the plurality of second hollow members;wherein the second flow passage is configured to receive a second fluidthat flows through the second flow passage and into the plurality offirst hollow members; wherein the first fluid is configured to exchangeheat with the second fluid as the first fluid flows through the firstflow passage and over the plurality of first hollow members; and whereinthe second fluid is configured to exchange heat with the first fluid asthe second fluid flows through the second flow passage and over theplurality of second hollow members.
 2. The heat exchanger of claim 1,wherein the first hollow members are attached to the separator memberand arranged in a first row of hollow members and a second row of hollowmembers; wherein the hollow members of the first row are attached to theseparator member at a first acute angle; and wherein the hollow membersof the second row are attached to the separator member at a second acuteangle that is different from the first acute angle.
 3. The heatexchanger of claim 2, wherein the first and second acute angles aresubstantially opposite each other.
 4. The heat exchanger of claim 1,wherein the first flow passage has an inlet and an outlet and a flowaxis extending between the inlet and the outlet; wherein at least one ofthe first hollow members has a first end and a second end and across-flow axis extending between the first end and the second end; andwherein the cross-flow axis is oriented with respect to the flow axis todirect flow through the at least one hollow member along the flow axis.5. The heat exchanger of claim 4, wherein the cross-flow axis issubstantially straight.
 6. The heat exchanger of claim 4, wherein thecross-flow axis is curved.
 7. The heat exchanger of claim 1, wherein thefirst hollow members have respective first cross-flow axes that aredisposed within a first plane; wherein the second hollow members haverespective second cross-flow axes that are disposed within a secondplane; wherein the first plane intersects the second plane.
 8. The heatexchanger of claim 7, wherein the first plane is substantiallyorthogonal to the second plane.
 9. The heat exchanger of claim 1,wherein the first hollow members have a respective first length; whereinthe second hollow members have a respective second length; and whereinthe second length is greater than the first length.
 10. The heatexchanger of claim 1, wherein the first hollow members have a respectivefirst cross sectional area; and wherein the second hollow members have arespective second cross sectional area; and wherein the second crosssectional area is greater than the first cross sectional area.
 11. Theheat exchanger of claim 1, wherein at least one of the first hollowmembers includes a projection, the projection chosen from a groupconsisting of a fin, a pin, and a helical projection.
 12. A heatexchanger comprising: a first separator member and a second separatormember, the first separator member dividing an intermediate flow passageof the heat exchanger from an upper flow passage of the heat exchanger,the second separator member dividing the intermediate flow passage froma lower flow passage of the heat exchanger, the upper flow passagehaving a first inlet and a first outlet and configured to direct flow ofa first fluid along a first flow axis from the first inlet to the firstoutlet, the intermediate flow passage having a second inlet and a secondoutlet and configured to direct flow of a second fluid along a secondflow axis from the second inlet to the second outlet; and a hollowmember that extends across the intermediate flow passage and that isattached to the first separator member and the second separator member,the hollow member being fluidly connected to the upper flow passage andthe lower flow passage, the hollow member being oriented with respect tothe first flow axis to direct flow of the first fluid through the atleast one hollow member along the first flow axis.
 13. The heatexchanger of claim 12, wherein the hollow member has a cross flow axisthat is substantially straight and that is oriented at a non-orthogonalangle with respect to the first flow axis.
 14. The heat exchanger ofclaim 12, wherein the hollow member has a cross flow axis that iscurved.
 15. The heat exchanger of claim 12, wherein the hollow member isone of a plurality of hollow members that extend across the intermediateflow passage and that are attached to the first separator member and thesecond separator member; wherein the plurality of hollow members arefluidly connected to the upper flow passage and the lower flow passage.16. The heat exchanger of claim 15, wherein the plurality of hollowmembers include a first group of hollow members and a second group ofhollow members; wherein the first group of hollow members are orientedat a first angle relative to the first flow axis and the second group ofhollow members are oriented at a second angle relative to the first flowaxis; and wherein the first angle is substantially opposite the secondangle.
 17. The heat exchanger of claim 12, wherein the hollow member hasa cross-sectional area that varies along a length of the hollow member.18. The heat exchanger of claim 12, wherein the first separator member,the hollow member, and the second separator member are integrallyattached to be unitary.
 19. A method of manufacturing a heat exchangercomprising: forming a first flow structure with a first flow passage anda second flow structure with a second flow passage, including forming aseparator member that divides the first flow passage from the secondflow passage; forming a plurality of first hollow members that extendacross the first flow passage and that are attached to the separatormember at respective non-orthogonal angles, the plurality of firsthollow members being fluidly connected to the second flow passage; andforming a plurality of second hollow members that extend across thesecond flow passage and that are attached to the separator member atrespective non-orthogonal angles, the plurality of second hollow membersbeing fluidly connected to the first flow passage; the first flowpassage being configured to receive a first fluid that flows through thefirst flow passage and into the plurality of second hollow members; thesecond flow passage being configured to receive a second fluid thatflows through the second flow passage and into the plurality of firsthollow members; the first fluid being configured to exchange heat withthe second fluid as the first fluid flows through the first flow passageand over the plurality of first hollow members; and the second fluidbeing configured to exchange heat with the first fluid as the secondfluid flows through the second flow passage and over the plurality ofsecond hollow members.
 20. The method of claim 19, further comprisingadditively manufacturing the first flow structure, the second flowstructure, the plurality of first hollow members, and the second hollowmembers to be unitary.